diff --git a/justfile b/justfile
index 6fd2e46..81d406e 100644
--- a/justfile
+++ b/justfile
@@ -95,12 +95,14 @@ mutants-mcp:
     MCP_CASES=16 PROPTEST_MAX_SHRINK_ITERS=0 TMPDIR={{mutants_tmp}} cargo mutants -p ledger-mcp --test-package ledger-mcp -j 4 --timeout 600 -o mutants-mcp
 
 # Mutation testing of the viewer where it matters: the numbers it shows
-# (the view model) and how it writes them (formatting). Its read-only
-# promise has its own test (tests/read_only.rs); search, history, ticks,
-# and the attention list are spec-tested, not swept.
+# (the view model) and how it writes them (formatting), against the tests
+# that check them (the unit tests and spec_gui). Its read-only promise has
+# its own test (tests/read_only.rs, which renders every page: too slow to
+# rerun per mutant); search, history, ticks, and the attention list are
+# spec-tested, not swept.
 mutants-gui:
     mkdir -p {{mutants_tmp}}
-    PROPTEST_MAX_SHRINK_ITERS=0 TMPDIR={{mutants_tmp}} cargo mutants -p ledger-gui --test-package ledger-gui -j 4 --timeout 180 -o mutants-gui -f crates/ledger-gui/src/books.rs -f crates/ledger-gui/src/fmt.rs
+    PROPTEST_MAX_SHRINK_ITERS=0 TMPDIR={{mutants_tmp}} cargo mutants -p ledger-gui --test-package ledger-gui -j 4 --timeout 60 -o mutants-gui -f crates/ledger-gui/src/books.rs -f crates/ledger-gui/src/fmt.rs -- --lib --test spec_gui
 
 # Benchmarks of the core's hot paths (no budget gates them yet)
 bench: